Book Review: Beginning Visual Basic 6 Databases

As programmers at the dawn of new millennium, our problem is one of data access. We
have been using Data Access Objects (DAO) in the book both to program our database and to
create new tables. But if there is a need to access data sources other than Microsoft
Access, the enterprise edition of Visual Basic 6.0 provides Remote Data Objects (RDO). RDO
permits Visual Basic programmers to work with relational ODBC data sources. And DAO/Jet is
used when we want to work with Jet and ISAM data sources. So traditionally, if we needed
to work with remote ODBC data sources we would select RDO. However, when we need to access
ISAM or Jet data sources, then DAO is the clear choice. But now Microsoft is offering us a
new and much more efficient approach that permits us to use a single high level, efficient
programming paradigm to work with everything. It's called Universal Data Access (UDA).

Universal Data Access is Microsoft's high-performance solution to access a variety of
information sources, including relational and non-relational data sources. UDA is an easy
to use programming interface - it is a tool and it is language independent. In other
words, UDA is really a bundle of technologies that enable us to integrate diverse data
sources, relational and otherwise. These tools permit companies to create easy-to-maintain
solutions, and take their pick of best of breed tools and application programs.

Universal Data Access does not require the expensive and time-consuming (and many times
impractical) shuttling of data from various databases into a single data store. Also,
companies are not required to commit to a single vendor's products - pretty attractive for
any IS department. Universal Data Access is based on open industry specifications: it
enjoys broad industry support and currently works with all major established database
platforms.

The way to employ UDA is by using ActiveX Data Objects. You can see that by using ADO,
we can access any data either by using tried and true ODBC or an OLE DB providers:

So you can see that our Visual Basic 6.0 application can use DAO as we have been doing
up till now. DAO can access Jet directly as we have been doing. This gives us the
interface into Access, Paradox, dBase, Excel, FoxPro, Lotus 1-2-3, and text files. We can
also use ODBC to talk to any SQL compliant data source. This can be accomplished either
through Jet, or ODBCDirect that bypasses the Jet engine. But consider the multitude of
steps that must be gone through under the hood.

Now, by using ADO, we can simply use the OLE DB provider for the specific data source
and voila! - we have connected. However, we can still employ the OLE DB provider for ODBC
to use ADO for communicating with any ODBC sources. So using ADO, we get everything we got
with DAO, and more. And, it is actually easier to use. Life is good.